Lawmakers are considering legislation that would marry the state’s water fluoridation standards with a federal recommendation issued last year, in turn lowering the maximum amount of fluoride that could be placed in the state’s public drinking water.

HARTFORD — Lawmakers are considering legislation that would marry the state’s water fluoridation standards with a federal recommendation issued last year, in turn lowering the maximum amount of fluoride that could be placed in the state’s public drinking water.

During a hearing on the bill this week, some advocates were pleased that the threshold would be lowered but asked that fluoride stop being added to the water supply all together, citing health concerns. Others, including several dentists, supported the legislation and testified that the mineral prevents widespread tooth decay in adolescents without adverse side effects.

Fluoride was first added to the public water supply since 1945 to protect against tooth decay. Last year, the federal government updated water fluoridation recommendations for the first time since 1962. The U.S. Department of Health and Human Services recommended a fluoride concentration of 0.7 milligrams per liter in public drinking water. The previous recommendation – in place from 1962 until 2015 – ranged from 0.7 to 1.2 milligrams per liter. Fluoride is also naturally occurring in water.

While the federal government recommends fluoridation levels, state and municipal governments decide whether the mineral should be added to public drinking water. In Connecticut, public water companies serving more than 20,000 people are required by state law to maintain a fluoride content of between 0.8 and 1.2 milligrams per liter. Legislation raised by the General Assembly’s Public Health Committee would instead require that the same water companies not add more than “one-tenth of a milligram per liter different” than the U.S. Department of Health and Human Services recommendation. Therefore, the maximum amount of fluoride that could be added to the state’s public drinking water is 0.8 milligrams per liter, instead of 1.2 milligrams per liter.

William Nash, president of the Connecticut State Dental Association and a practicing dentist for 38 years in Fairfield, testified in support of the legislation during a hearing before the Public Health Committee Wednesday. The federal government recommended lower fluoride levels last year due to new sources of intake – such as food, toothpaste and professional treatment – that have arisen in recent decades. The pending legislation allows the state to alter fluoridation levels based on federal recommendations “without a change of statute,” Nash testified.

“Fluoridation has a long history of safe and effective reduction of dental decay, also known as dental caries,” he said, noting that after fluoridation of public water began in 1962, the number of 12-19 year olds with one or less cavities increased from 60 percent to 90 percent.

Several dentists submitted similar testimony, while state Department of Public Health Commissioner Raul Pino offered his support as well. Pino said that 91 percent of residents connected to public water systems in the state have access to fluoridated water.

State Sen. Joe Markley, R-Southington, a ranking member of the committee, said only 13 states in the country mandate that fluoride be placed in the public water system.

Three years ago, Markley put forward a bill that would leave it up to municipalities to decide if fluoride should be placed in drinking water. That bill failed.

“If there is a legitimate question, we probably shouldn’t be putting it in the water,” he said.

Several people argued during the hearing that fluoride in drinking water is unethical and dangerous. They asked that the mandate be removed in its entirety. Some testified that it is unethical to put fluoride in public water.

Lindy Urso, an attorney, said there is no way to control the dosage of fluoride when it is administered through drinking water.

“In other words, one person may drink 12 ounces of fluoridated water daily, while anther may drink 120 ounces,” she testified. “Clearly the latter person who drinks more is at a much higher risk of experiencing the negative side effects than the former. And it can’t be disputed that there are side effects.”

Urso referred to a 2012 Harvard School of Public Health analysis of 27 studies, mostly from China. Several of the Chinese studies found that high levels of fluoride in children negatively impacted cognitive development. In the Department of Health and Human Services recommendation on water fluoridation issued last year, reference was made to the Chinese studies. The recommendation states that while more research is warranted, the studies omitted processes. A review from the Scientific Committee on Health and Environmental Risks, part of the European Commission, found there was “not enough evidence from well-controlled studies to conclude if fluoride in drinking water at concentrations used for community fluoridation might impair the IQ of children,” the recommendation states.

Thousands of studies have found fluoride to be safe, according to the Centers for Disease Control and Prevention. But with increased sources of fluoride in food and toothpaste, there has been an increase in dental fluorosis – 90 percent of which appears as white spots on the tooth surface.

Lowering the fluoride concentration in public water was suggested in part to “decrease fluoride exposure during the time of enamel formation, from birth through 8 years of age for most permanent teeth, and further lessen the chance for children’s teeth to have dental fluorosis, while keeping the decay prevention benefits of fluoridated water,” last year’s recommendation from the U.S. Department of Health and Human Services states.

Severe dental fluorosis can include the pitting of teeth, though this condition is rare, according to the agency.